feat: default MiniMax examples to M3.1 Flash

[octo-patch]

Reason: Make the MiniMax example select MiniMax-M3.1-Flash by default while retaining MiniMax-M3 as an opt-in ensemble member.

Changes

• Add the MiniMax configuration with Flash enabled for evolution and evaluation. M3 has zero weight until explicitly enabled; older model IDs are no longer advertised in the example.
• Document both regional endpoints, current context windows, and Flash effort settings. Remove the unsupported per-iteration cost estimate and stale temperature guidance.
• Exercise configuration loading, ensemble selection, and real SDK serialization with an offline HTTP transport. Cover regional URLs, default requests, all five Flash effort levels, explicit M3 selection, saved/custom model IDs, and preservation of image/video content parts.
• Preserve existing configuration semantics and the generic API transport. Explicit model names are never rewritten.

Validation

• Python 3.10.12, installed with pip install -e ".[dev]"; Black 25.12.0 and isort 7.0.0 match the repository's hook pins.
• python -m unittest discover -s tests -p test_minimax_config.py -v: 4 passed, including controller initialization and SDK serialization against mocked HTTP transport.
• python -m unittest discover -s tests -p 'test_*.py' -v: 691 tests run, OK (2 circle-packing tests skipped because optional SciPy is not installed).
• black --workers 2 --check tests/test_minimax_config.py tests/test_valid_configs.py: passed.
• isort --check-only tests/test_minimax_config.py tests/test_valid_configs.py: passed.
• git diff --check and diff secret scan: passed.

Tests ran in a checkout-local environment without inherited provider or automation credentials. The separate optillm/model integration suite was not run.

References

• https://platform.minimax.io/docs/api-reference/text-openai-api

No paid inference is used. At head 679f5cc8685feff2b5c27e37d612589bfaa5fc92, the upstream Tests and Security Scan workflows report action_required, and license/cla is pending because the CLA is not signed. These checks require separate resolution before merge; hosted CI has not passed.

[CLAassistant]

Thank you for your submission! We really appreciate it. Like many open source projects, we ask that you all sign our Contributor License Agreement before we can accept your contribution.
0 out of 2 committers have signed the CLA.

❌ PR Bot
❌ octo-patch

---

PR Bot seems not to be a GitHub user. You need a GitHub account to be able to sign the CLA. If you have already a GitHub account, please add the email address used for this commit to your account.
_{You have signed the CLA already but the status is still pending? Let us recheck it.}

[octo-patch]

I've updated the commit author to be properly linked to my GitHub account. The CLA check should pass now. @CLAassistant check